Essential Mathematical Formulas for PMP Certification Test
A = B + C
PERT (Program Evaluation and Review Technique) estimate standard deviation is a method of determining how much uncertainty or variance there may be in the time it takes to accomplish a project job.
Assume you’re working on a diorama for a school project. You estimate it will take roughly 4 hours to complete, but you’re not certain because things sometimes take longer or shorter than intended.
The standard deviation of the PERT estimate lets you realize how much your actual time may change from your first estimate. Assume the standard variation for your diorama project is one hour.
If your anticipated time is 4 hours with a standard deviation of 1 hour, that implies that there is a 68% chance that your actual time will be between 3 and 5 hours. As a result, the greater the standard deviation, the more probable it is that your real time will deviate from your initial estimate.
When planning projects, project managers can use this statistical metric to account for uncertainty. It offers an indication of how long a task could take after the original estimate.
Practice Test
Example
Assume you predict a work will take 10 days with a PERT standard deviation of 2 days. Because of the unpredictability or uncertainty involved, there is a strong possibility the work will take between 8 and 12 days (10 days 2 days).
